William d



(No'ModeL) .W. 1). HOOKER.

BALANCED VALVE.

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NIT'ED STATES PATENT OFFICE.

\VILLIAM l). HOOKER, OF OAKLAND, CALIFORNIA.

BALANCED VALVE.

SPECIFICATION forming part of Letters Patent No. 253,166, dated January31, 1882.

Application filed June 8, 1881. (E0 model.) i

To all whom "it may concern Be it known that 1, WILLIAM D. HOOKER, ofthe city of Oakland, in the county of Alameda and State of California,have invented certain new and useful Improvements in Balanced Valves forSteam-Engines; and I do hereby declare that thefollowing is afull,clear,and exact description thereof, reference being had to the accompanyingdrawings.

My invention relates to an improved method and arrangement for balancingthe steampressure on slide-valves that are moved by or with or in afixed relation to a supplemental piston; and itconsistsintranferringtlle pressure fromtiie slide-valve to the supplementalpiston, and then counteracting the pressure on the piston by exposing acorresponding area of the piston to the steam-pressure in a counterdirection, all as hereinafter described.

Referring to the accompanying drawings, Figure 1 is a verticallongitudinal section. Fig. 2 is a transverse section through the centerof the valve-chamberand the supplemental piston.

Let A A represent a supplemental piston which is moved by steam or otherpressure in the main-valve chamber of an engine, and with which the mainvalve B, which admits steam to and exhausts it from the engine-cylinder,is connected so as to be moved by or with it. Usually this supplementalpiston consists of two heads and a connecting-stem of smaller diameter,as represented in the draw ings, and the .main valve B is carried in arecess in its under side. As herein represented, the heads of thissupplemental piston are made hollow, and they are connected by two bars,0 0. (Shown at Fig.2.) In constructing these bars I cast or otherwiseform a ledge, rib, or lug, d,

on the inside of each, so that the two lugs will be opposite each other.I then take an inverted-cup-shaped cylinder, E, on the opposite sides ofwhich a corresponding lug or rib, e, is formed, and drop it down betweenthe bars 0 0 until its lugs orribs erest upon the lugs or ribs d. Thisarrangement I have adopted becauseit is simple and answers every purpose5 but the cylinder can be secured to or mounted upon the piston in theposition represented in any other way. The slide-valve B fits in therecess between the heads A A of the supplemental piston and below theinvertedcup-shaped cylinder E.

To the upper side of the slide-valve I attach a piston, G, which willextend up into the cylinder E when the main valve is in position betweenthe heads A A. This piston can be cast as a part of the valve, ifdesired. In the draw,- ings it is represented in theform of a cup; butit can be made like any other piston, its object being to fit in thecylinder E and make a comparatively tight joint which will prevent thesteam from passing into the cylinder above it. A port or passage,t',leads from the space above the piston G down through the piston and mainvalve, so as to connect the space above the piston in the cylinder withthe exhaustpassage; or it might be connected with the open air withequal advantage, its object being to prevent any steam-pressure in thespace. Now, when steam isadmitted into the valve chamber it will pressupon the top of the inverted cylinder E and upon the exposed portion ofthe valve that projects around the piston; but it will not enter thespace in the cylinder above the piston. Oonsequen tly there will be nopressure in the space, and the valve will be relievedin proportion tothe areas of the piston and valve, respectively. Should any portion ofsteam gain entrance to the space above the piston, itim mediate] ypasses through the port 1' to the exhaust or to the open air, so that itis impossible to obtain any pressure upon the piston.

In constructing the valve B, piston G, and cylinder E, I regulate theirrespective areas according to the amount of pressure I desire to takeoffthe main va1ve. By this arrangement the valve is free to lift when thepressure underneath it exceeds the pressure above it, because the pistonG can move upward in the cylinder. Should the valve-rod, therefore, orany of its connections with the engine become detached or broken, themomentum of the engine will continue to move the piston until theresistance and friction stops it, in which case the pressure in thecylinder will lift the slidevalve from its seat, and thus fill thecylinder with steam, thus preventing any damage. As stated, thisrelieves the pressure on the valve; but it is evident that the pressurethus taken off the valve is only transferred to the supplementalpiston,because the cylinderE rests upon the supplemental piston, and thepressure comes on top of the cylinder and pressesthe supplemental pistondownward. This pressure on the supplemental piston can be relieved invarious ways; but the simplest method is to make a port or opening, 9,in the val ve-chamber above each hollow head A A of the supplementalpiston, so as to connect the interior of the chamber with the open airat such a point that each opening will be covered by the moving pistonduring its entire stroke, and thus prevent the escape of the steam. Thecombined area of these openings being equal to the area of the cylinderE, the upward pressureot' the steam in the hollow piston will counteractthe downward pressure upon the cylinder E, thus balancing the valve andpiston both horizontally and vertically throughout the entire length oftheir stroke.

To insure an easy motion of the supplemental piston, and at the sametime preserve a tight joint between the steam-space and the opening g, Iplace a packingring, 8, around each piston-head, on each side of theopening.

When the ends of the supplemental piston are solid, and the piston ismoved by steam, either through the medium of an auxiliary valve orotherwise, I provide a recess under each end of the supplemental piston,the com' bined areas of which are equal to the area of the cylinder E,so that the live steam will fill the recesses and exert an upwardpressure corresponding to the downward pressure on the piston. A verysuitable arrangement for this purpose is shown in my Letters Patent No.81,168, which was issued to me on the 18th day of August, 1868, in whicha puppet-valve is consisting in transferring the steam-pressure from thevalve to a supplemental cylindrical piston, and then counteracting thepressure upon the piston by exposing a corresponding area of the pistonto the steam-pressure in a counter direction, substantially asdescribed. 2. The inverted-cup-shaped cylinder E,'at-

tached to the horizontally-moving supplement al piston A A, incombination with the slidevalve B, with its piston G fitting in thecylinder E, and having the space above it connected with the exhaust oropen air by a passage, 0', substantially as described.

3. The hollow supplemental piston A A, arranged to move in a case orshell having a space, 9, connected with the open air, in combinationwith the inverted-cup-shaped cylinder E and main valve B, with itspiston G and the passage 1', all combined and arranged to operatesubstantially as above described.

In witness whereof I have hereunto set my hand and seal.

WILLIAM DAVIS HOOKER. ['L. s] Attest:

W. F. CLARK,

W. Vorr.

